"Ange, you seem a bit irritated and prickly with some answers today - is that a sign of uneasiness and pressure?" Harris asked the Australian coach.

Postecoglou replied: "You must know me really well - how many times have you met me? First time? Maybe that's just my demeanor - there is your answer."

The Socceroos have brought a full-strength squad to the Russian-based tournament, unlike their first-up opponents Germany - who only have three players selected that featured in their 2014 World Cup triumph.

When asked why the Socceroos had selected all their big guns as opposed to other teams, Postecoglou looked visibly frustrated.

"Because we want to continue to evolve as a team and we want to do well here," he said.

"I’m not really sure if that’s a trick question or something. But I usually pick my best team."

Australia take on the Germans on Tuesday morning (1am AEST) in their first group B match before facing Cameroon and Chile.